The ethical and moral debate over expanding embryonic stem cell research could motivate voters on both sides of the issue in this year's U.S. congressional elections.

Embryonic stem cells are master cells within the fetus that can develop into any form of human tissue.

Supporters of expanding stem cell research contend it has the potential to help treat diseases like Alzheimer's, Parkinson's and diabetes, as well as some spinal cord injuries.

Cody Unser was stricken with a rare spinal cord infection that has left her a paraplegic.

"Over 100 years ago, man could not fly. All I want to do is walk again. Stem cell research is my answer. Do not let me and others who are suffering wait any longer," he said.

Advocates have focused on expanding embryonic stem cell research because scientific experiments have shown them more adaptable than adult stem cells.

But opponents of expanding stem cell funding counter that it is immoral to destroy the embryos used in the research, arguing they represent the earliest form of human life.

In fact, the stem cell issue became the subject of President Bush's first congressional veto. In July, the president struck down an attempt by lawmakers to lift federal funding restrictions on human embryonic stem cell research.

"In this new era, our challenge is to harness the power of science to ease human suffering without sanctioning the practices that violate the dignity of human life," said Mr. Bush.

Mr. Bush says the pre-existing stem cell lines that are currently the subject of federally funded research are adequate and that taxpayers should not support expanded research on surplus embryos at fertility clinics, even if they are slated for disposal.

Conservative religious activists welcomed the president's veto. They oppose the use of human embryos for stem cell research and praise couples who adopt the embryos, implant them in a woman's womb and bring them to term.

But opinion polls indicate that most Americans are generally supportive of expanding stem cell research and excited about the potential they represent for combating diseases.

Even some notable Republicans have broken with the president on the issue. They include Senate Republican leader Bill Frist, a heart surgeon from Tennessee, and former First Lady Nancy Reagan, whose late husband, former President Ronald Reagan, battled Alzheimer's disease.

Political analysts believe the stem cell issue could have an impact on some of the congressional races in November when Republicans attempt to hold majorities in both the Senate and House of Representatives.

John Fortier monitors U.S. politics at the American Enterprise Institute in Washington.

"You have people who are pro-life behind the president and that may help Republicans in certain [congressional] districts," he explained. "But in northeastern districts, Democrats, I think, will be helped in certain swing or moderate districts where Republicans are put in a difficult position."

Conservative groups that emphasize opposition to social issues like homosexual marriage and abortion hope to seize on the stem cell issue as a way of boosting voter turnout in November.

Stuart Rothenberg publishes an independent political newsletter in Washington.

"This is one of those elections where while Democratic enthusiasm is up, at the moment, the early indications are that Republican enthusiasm is down," he noted.

Democrats believe their support for expanding stem cell research will appeal to independent and even moderate Republican voters who disagree with President Bush over the issue.

In the Midwest state of Missouri, voters will decide on a ballot initiative that would protect stem cell research. The issue has also become a hot topic of debate in the Missouri Senate race between Republican incumbent Jim Talent and his Democratic challenger, Claire McCaskill.